1. Technical Field
The present technology relates to a pneumatic tire provided with a row of blocks constituted by a plurality of blocks aligned in a tire circumferential direction on a tread portion and provided with a plurality of sipes on each block, and more specifically relates to a pneumatic tire whereby both running performance on dry road surfaces and running performance on snow can be achieved at a high dimension.
2. Related Art
In pneumatic tires for winter, such as studless tires, a plurality of circumferential grooves that extend in the tire circumferential direction and a plurality of lug grooves that extend in a tire width direction are formed in the tread portion, a plurality of blocks is partitioned by these circumferential grooves and lug grooves, and a plurality of sipes extending in the tire width direction is formed in each block (see Japanese Unexamined Patent Application Publication No. H7-257114A, Japanese Unexamined Patent Application Publication No. 2000-280712A and Japanese Unexamined Patent Application Publication No. 2009-274669A).
In this type of pneumatic tire, increasing the number of lug grooves and sipes extending in the tire width direction increases the snow traction and enables the running performance on snow to be improved. However, there is the problem that excessive lug grooves and sipes cause decrease in running performance on dry road surfaces due to a decrease in block rigidity.
Particularly, in recent years, for the running performance on dry road surfaces, while there is a demand to increase steering stability including high-speed lane changeability in a high-speed environment such as that exceeding 200 km/h, there is a demand to further improve the running performance on snow, but currently this cannot be accommodated with conventional tread structure.